Here is a simple diagram that will help you to understand how a notebook display assembly works and how an image appears on the screen. I’m not an artist and I tried my best drawing this diagram, so if you cannot see a laptop in this picture, don’t be mad. 
A generic display assembly includes a very few parts and knowing them will help you to understand witch part can cause a problem if you laptop video not working properly.
Video cable. A video signal from the motherboard goes to the LCD screen through the video cable. The video cable connects to the motherboard (or video card) through the connector 1. The video cable connects to the LCD screen through the connector 2. The video cable (in most cases) is also responsible for supplying a necessary voltage for the FL inverter board. The video cable connects to the FL inverter board at the point 3.
FL inverter board. This board is responsible for converting low voltage DC power (point 3) to high voltage AC (point 4), necessary to light up the backlight bulb. If the FL inverter board is bad, the LCD screen (backlight bulb) will not light up when you turn on the laptop, but you still should be able to see a very dim image on the screen.
Looking for a new screen, video cable or inverter board? Find it here.
CCFL (backlight bulb). When the backlight bulb lights up, you can see an images on the LCD screen. In most cases the backlight bulb is a part of the LCD screen and if it’s bad, the entire screen has to be replaced. By the way, some specialized repair shops can replace the backlight bulb itself.
Lid close switch. The lid close switch is a small button that locates close to the display hinges. On some newer models there is no button, because the switch is magnetic. You can set up your laptop to go to a hibernation mode or to a standby mode when the LCD is closed. It’s done through power management software. These modes are triggered when the display is closed and the lid close switch is pressed down. If the LCD screen on your laptop will not light up when you open the display assembly, check the lid close switch is stuck inside (it might happen because the switch is dirty).
Related articles:
Fixing notebook video problems.
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April 10th, 2007 at 10:40 pm
Aaron N,
What do you mean by “screen will bugg out”? The backlight goes off, the video disappears, the image changes colors or what?
April 10th, 2007 at 3:31 pm
Hi Laptoprepairguy,
i have a broken thinkpad a31 and i would like to use it’s display as an external monitor. Do you know where i can get any information about the display-cable layout? Or the layout of the header?
Thanks for your help,
Falk
April 10th, 2007 at 1:14 pm
Hello i have a IBM R60e (im pretty sure) and i use it for playing games but recently when playing games the screen will bugg out when it is moved from a flat position and the only way i can get to go back to normal is by shutting down the Pc all together. PLEASE HELP!
April 8th, 2007 at 11:37 pm
Josh Porter,
Looks like a screen inverter problem to me. I think there is nothing wrong with the lid close switch and most likely you have a faulty inverter board. I would try replacing the inverter first, it might help you to fix the laptop.
April 8th, 2007 at 10:41 am
i am having a similar problem, although it is not due to a bad backlight. my problem lies with the lid close switch. if i rapidly push the switch for a few eventually it will come on and stay on for a while. i hahe torn the whole thing down to the board itself to check the connection for the switch itself and the connection seems good, and no broken traces. so i have determined the problem to be my lid switch. any ideas where i can buy a new switch?
April 7th, 2007 at 3:08 am
Dear Fellow
I have removed the laptop screen and wish to use the said screen as monitor but there is a problem that the connectors which are pluged in the motherboard i have placed out.But how can i use them, there are 2 kinds of connector, one is Vedio n the other i for 12 Volt supply. Can anyone let me know that how could i connect both of them
April 4th, 2007 at 11:02 pm
Hello,
I have a Spartan laptop with 17″ display and since this was a fairly pricey unit, my heart stopped when the display failed! I was picturing a fairly expensive repair or worse…
I followed the numerous posts here, regarding failed lcd displays and finaly, the culprit was a simple one: a stuck lid switch (the laptop simply thought the lid was closed and had shut down the lcd display to save power.)
I am relieved and I just wanted to say thank you very much! You guys are great
A very relieved laptop user.
Mustapha
P.s., I do “security” at a local bar and have to charge admission fee’s for our events and you guys can only guess how boring it can get. Well, I usually take along my laptop to help maintain sanity and in between checking id’s and charging admission, I usually browse the web or spend time going through youtube.com video’s. If my laptop had broken, well… it would have meant very boring shifts and ensuing madness
March 28th, 2007 at 3:47 pm
I have a problem with the user here when he logged in he find that the keyboard is not function but when another user logged in the computer just function properly. what is the problem can you help me? with this
March 27th, 2007 at 9:07 am
I have a HP Pavilion N3270 with a faulty screen. It is very faint when the laptop boots up, and then goes blank. An external monitor works OK, and when I switch between the laptop screen and the monitor, the laptop screen appears OK for about 1-2 seconds, and then goes blank.
Thanks for your help
March 24th, 2007 at 6:27 pm
I have a toshiba a15-127 with a sharp lq150×1lhc3 a lcd. I am having difficulty finding a backlight tube online. Is a separate tube available? Thanks for your help, Mike